After leaving the U.S. Senate in 1993, Symms founded Symms, Lehn Associates, Inc., a consulting firm. In January 1999, he partnered with John Haddow and formed Symms & Haddow Associates, a lobbying firm. In January 2001, the firm joined forces with Romano Romani and former Senator Dennis DeConcini of Parry, Romani & DeConcini to form Parry, Romani, DeConcini & Symms.

Prior to his senior year at Idaho, Symms married college sweetheart Frances E. "Fran" Stockdale of Helena, Montana,[16] in August 1959.[2] They had four children, a son and three daughters. Following his re-election in 1986, the couple separated,[5] and their divorce was finalized in 1990.[4] Symms married Loretta Mathes Fuller in 1992,[1] a former aide and later the Deputy Sergeant of Arms of the U.S. Senate.

Senator Symms was one of several Republican senators who in 1981 called into the White House to express his discontent over the nomination of Sandra Day O'Connor to the Supreme Court; the opposition hinged over the issue of O'Connor's presumed unwillingness to overturn Roe v. Wade.[17]

During the 1988 U.S. presidential election, Symms claimed in a radio interview that a photograph existed from the 1960s showing Kitty Dukakis, the wife of Democratic presidential candidate Michael Dukakis, burning an American flag to protest the Vietnam War. Kitty Dukakis angrily denied the accusation as "totally false and beneath contempt," and Symms later admitted that he could not substantiate it.[18] Nevertheless, the claim became national news, as media outlets began searching for the photograph Symms said he had "heard" about.[19] The flag-burning story was one of several false rumors about Dukakis that circulated during the 1988 campaign. "Mr. Symms's comment was the third time in a few days that prominent Republicans have publicly aired allegations that the Democrats have swiftly rebutted," the New York Times reported.

^"Seniors". Gem of the Mountains, University of Idaho yearbook. 1959. p. 300.

^Greenburg, Jan Crawford. Supreme Conflict: The Inside Story of the Struggle for Control of the United States Supreme Court.2007. Penguin Books. Page 222.

^AP Editors (August 26, 1988) "Story on Mrs. Dukakis Is Denied by Campaign." New York Times.

^Dionne. E.J. Jr. (August 29, 1988) "Political Memo; Accentuating the Positive Can Lead to Nasty Campaign." New York Times. The story read: "This campaign got very rough very early, and Kirk O'Donnell, a senior adviser to Mr. Dukakis, said it was shaping up to be among the most negative recent presidential contests. Pointing a finger at the Bush campaign, he said, 'There's no question that rumor has developed into a new art form in this campaign. He was referring to a recent statement by Senator Steve Symms, Republican of Idaho, who said that he understood there were pictures showing that Kitty Dukakis, the candidate's wife, had burned an American flag. Mrs. Dukakis angrily denied the accusation, and Mr. Symms later acknowledged that he had no proof. But it was on television before he drew back."